如评论中所述，错误似乎不是您的代码的问题而是阻碍沟通的东西。也许服务器IP错误，或端口，或凭据或您有防火墙问题。你必须全力以赴才能弄明白。

As stated in the comments, the error does not appear to be an issue with your code but rather something blocking the communication. Perhaps the server ip is wrong, or the port, or the credentials or you have a firewall issue. You'll have to work through it all to figure it out on your end.